1. Field of the Invention
The present invention relates to compositions comprising ecdysteroid and methods of using the compositions to treat or prevent a physiological condition related to growth hormone.
2. Description of Related Art
Growth hormone (GH) plays a key role in growth and metabolism. Growth hormone, also known as somatotropin, exerts some of its effects directly on the tissues and other effects indirectly by inducing the synthesis of growth factors. The most important of these growth factors are the insulin-like growth factors (Butler and LeRoith, Annu. Rev. Physiol. 63:141-64, 2001).
GH has wide-ranging developmental effects on the organism. GH administration to animals induces protein synthesis in muscle and positive nitrogen balance (Kostyo, Ann. NY Acad. Sci. 148:389-407, 1968). GH administration also enhances amino acid uptake into skeletal muscle, suggesting that this tissue is a primary target (Segard et al., Cellular Signaling 15:615-623, 2003).
In cases where increased levels of growth hormone are desired, treatments have included providing exogenous growth hormone, and administering GHRH or other peptidyl compounds which stimulate growth hormone production or release. In such cases, the peptidyl nature of the compound has necessitated that it be administered by injection. There is a need for a treatment that is simpler to administer and less painful.
Various health issues and disease states have been traced to deficiencies in maintaining normal growth hormone levels. For example, certain medical conditions associated with aging are due to age-related reduction in GH levels. Administration of growth hormone is used to treat conditions related to growth hormone deficiency. Clinical studies indicate that growth hormone supplementation may be useful in combating the maladies of aging in humans. Growth hormone is also used to treat human dwarfism.
Treatment of GH-deficient individuals with human GH has been shown to increase muscle size (Wolf et al., Surgery 112:284-91, 1992). GH therapy increases whole body protein synthesis, enhances nitrogen retention, and consequently increases the lean muscle mass (Wolf et al., 1992, supra).